Method for removing particulate matter and gases from a polluted gas stream

ABSTRACT

The steps of the method of the invention are preferably practice on apparatus consisting of components arranged in a closed system for removing particulate matter and gases from a polluted gas stream that includes a sorbent particulate charging and injection gun for electrostatically charging sorbent particles and injecting them into a polluted gas stream to charge and agglomerize pollution particulates therein, the stream flowing into a collection system housing that contains a series of moving and static bed filters and provides for operations at pressures less than atmospheric, and at temperatures up to two thousand (2000) degrees F. The filter beds are maintained across the housing and spaced apart from front to back therein, each filter containing a media material selected for removing the charged agglomerized pollution and sorbent reacted particulates and reacting with gases in the polluted gas stream, providing for removal thereof to clean that gas stream that is then vented to atmosphere. At least one and preferably a plurality of moving bed filters are arranged in the collection system housing, each, in turn, receiving and passing the gas stream therethrough, which filter beds each including rotary airlock and rotary valves for maintaining a closed system and preventing infiltration of outside air within the housing while still allowing new media materials to be added and vented out of the filter, and a static bed filter is used as a final clean up filter.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to methods for removing particulatematter and gases from a polluted gas stream, and more particularly tomethods involving adding of electrostatically charged sorbent particlesto a polluted gas stream containing particulate matter that becomescharged and adheres to the sorbent particles that are then removed,along with the sorbent reacted gaseous pollutants, in a series of movingbeds of granular material with the removed materials recovered for useor disposal and the cleaned gas vented.

2. Prior Art

Only in recent years have air pollution control apparatus and methodsbeen developed for the efficient and effective removal of fineparticulate matter, particularly submicron particles produced in highvolume processes. Earlier particulate removal methods and systemsexperienced substantial difficulties when they were required to meetstrict requirements and regulations as have been imposed by governmentalagencies for the removal of such particulate matter. Also, the removalof noxious gases has often present problems of a generation ofnon-disposable wastes as were produced in earlier industrial gascleaning methods and systems.

Only recently have systems been implemented that overcome some of theabove set out difficulties. Specifically, U.S. Patents to Schuff, U.S.Pat. Nos. 4,220,478 and 4,290,786, are directed, respectively, to amethod and to an apparatus, for removing particulate matter from a gasstream that, like the present invention, involve injectingelectrostatically charged particles of a sorbent material into a gasstream to form a large charged surface area to induce charging theparticulate matter entrained in the gas stream. The charged particlescontained in the gas stream together with the injected particles arepassed through a porous moving bed of media of granular materials,wherein, as a result of the electrical charge on the particles and theinertial impact forces of the respective particles, the particles attachto the changing media. The media, together with attached sorbentadditive and particulate matter are then separated for use in a productmanufactured from which generated particulate matter or are disposed of,with the cleaned gas leaving the moving media for venting.

Like the earlier Schuff patents, the method of the present inventionpreferably utilizes an electrostatic charging gun for imparting a strongelectrostatic charge onto sorbent particles introduced into the pollutedgas stream. The sorbent particles all bear the same charge and therebyrepel one another and are accordingly rapidly dispersed through the gasstream, creating a large charged surface area inducing charging of theparticulate matter within that gas stream. This charged surface tends toagglomerate the submicron and larger particulates with the gaseouspollutants chemically reacted with the charged sorbent particles andwith the media bed materials. The gas flow containing agglomeratedparticulates and sorbent particles with captured pollutants is thenpassed to moving media bed arrangements for the filtration andcollection of the sorbent reaction product and particulates and gasesfrom the gas stream, cleaning the gas stream that is then vented toatmosphere. The Schuff apparatus and method for its use, however,present limited capacity for particulate removal from high volumepolluted gas flows. The present invention overcomes these deficienciesby including a practice of steps of the invention where the sorbent flowcan be controlled and the electrostatic charging of the sorbentparticles can be adjusted, and provides multiple moving beds of the sameor different media material, each to present a large surface area ofexposure to the gas flow containing sorbent reaction products andparticulates, with the inclusion of a static bed for complete pollutantremoval. Additionally, unique from the Schuff patents, the presentinvention the moving beds are contained within a housing that includesan airlock system that has a capability for maintaining the beds at apressure less than atmospheric without the infusion of outside air,providing for a more efficient contaminant removal with the preferredsystem wherein the method of the invention is practiced being capable ofoperating at temperatures up to two thousand (2000) degrees F.

SUMMARY OF THE INVENTION

It is a principal object of the present invention to provide a methodfor removing both submicron and larger pollutant particulates andgaseous pollutants from high to low volume gas streams and for venting apollutant free gas flow to atmosphere.

Another object of the present invention is to provide a method for theremoval of both submicron and larger particulates of pollutants andgaseous pollutants from a polluted gas stream that is adjustable to awide range of pollutant volumes as are contained in a gas stream thatfunctions at less than atmospheric pressure.

Another object of the present invention is to provide a method for theremoval of pollutant particulates and gaseous pollutants from a gasstream that takes place at temperatures of up to two thousand (2000)degrees F.

Another object of the present invention is to provide a method for theremoval of pollutant particulates and gases from a gas stream thatutilizes a system for providing an injection of electrostaticallycharged sorbent particles into the gas stream, the particles to repeleach other and are rapidly dispersed throughout the polluted stream,which injection of charged sorbent particles is variable to accommodatea particular gas stream that contains from high to low volumes ofpollutants.

Still another object of the present invention is to provide a method forthe removal of pollutant particles of submicron and larger and gaseouspollutants from a polluted gas stream that utilizes a system forproviding an infusion of electrostatically charged sorbent toagglomerate the pollutant particles and then provides for separating theagglomerated particles and gaseous pollutants from the stream by serialpassage of the stream through a plurality of moving beds of mediamaterial as are suitable, and may be the same or different materials, toprovide for that agglomerized particulate and sorbent reactedparticulates removal and with a passage through a static filter bed tofinally remove essentially all the pollutant materials from the gasstream that is then vented to atmosphere.

Still another object of the present invention is to provide a methodthat involves agglomerizing and the removal of pollutant particulatesand gaseous pollutants from a gas stream that then provides for refiningout those removed agglomerized particulates from a moving bed mediamaterial containing those captured particulates for processing for useor disposal.

Still another object of the present invention is to provide a methodwhose practice provides for removing essentially all pollutants from avariety of gas streams that is practiced in a system that operates overa wide range of temperatures and at a pressure below atmospheric that issafe and reliable to use and is relatively inexpensive to maintain as,with operations at high temperature, corrosive gases and/or liquids arenot to created that could damage the equipment.

Still another object of the present invention is to provide a methodthat is practiced in a simple robust system that has relatively lowpower requirements, utilizes inexpensive material for moving media bedfilters of the system and sorbent materials as are used in the system,and is easy to operate.

These and other objectives of the method of the present invention willbecome apparent to those knowledgeable and skilled in the art with thedescription set out below.

A practice of the method of the invention provides for a removal of abroad range of pollutants as are encountered in a gas stream generatedby an industrial operation. Federal Environmental Agencies require areduction of such pollutant presence in a gas stream in compliance withcounty, state, and federal guidelines, requiring an effective removal ofall of such pollutants, including: particulates, condensible solids,acid mist (including sulphur trioxide--SO3, sulfuric acid--H2SO4,hydrochloric acid--HCL), sulphur dioxide (SO2), halogen gas, and VOC's.

Briefly, and in accordance with one embodiment of a preferred system forpracticing the method of the present invention, the modular apparatus ofthe system provides modular components arranged together for injectingelectrostatically charged sorbent particles into a polluted gas streamfrom one or more charged dry sorbent injection guns. Each such gunprovides a high voltage corona discharge that a flow of sorbentparticles is passed therethrough, the sorbent individual particles toreceive a strong electrostatic charge. The charged sorbent particles arethen injected into the polluted gas stream.

The preferred injection gun of the invention is arranged to provide avariable corona discharge to accommodate different flows of sorbentmaterials as have been selected for a particular gas stream pollutioncondition. The invention further provides, as required, for theinclusion of multiple injection guns, each to receive a select volume ofsorbent flow for providing a required sorbent particle presence in thegas stream, which presence is engineered to be sufficient to react withall the pollutants in that gas stream.

The charged sorbent particles are passed under pressure into theinjection gun and are preferably fine grain particles that all bear thesame charge, that like charge condition tending to rapidly disperse theparticles in the gas stream. The charged sorbent particles therebyprovide a large charged surface area for inducing like charges onto theparticulate matter entrained within the incoming gas stream. The gasstream particulate matter, consisting of submicron and larger particles,and the sorbent particles, thereby all carry the same charge and arepassed together into a transition section of a collection chamberhousing that includes a diffusion cone. The transition section has amuch greater area than that of the line transporting the gas stream,causing a rapid decrease in gas flow velocity with the diffusion conedirecting the gas stream over the surface of a first moving filter bed.This change in velocity causes some of the heavier particles in the gasstream to precipitate out of that flow, falling in front of the first ofa plurality of vertical filters that are each moving beds containing agranular media.

Each granular media moving bed is maintained across the gas stream flowpath, and is contained to move downwardly between spaced apart punchplates, that are sections of a mesh material, or like plates, that areopen therethrough to freely pass the gas stream. Front and rear punchplates of each bed are preferably spaced approximately twelve (12)inches apart, and contain granular materials that are selected to besuitable for reacting with the charged pollutant and sorbent particles,agglomerizing therewith into large particles, that are removed bescreening, or like method, the sorbent particles to also react with thegas stream gaseous pollutants. The agglomerated particles are screenedfrom the granular media and are then passed for processing the pollutantmaterials therefrom for use or disposal. Whereafter, the now cleangranular media is recycled for passage again through a moving bedfilter.

Each bed of granular media materials is a gravity flow bed, the granularmedia materials passing into the bed from a hopper that is fed through avalve with the media and captured pollutant and sorbent particles letdown and passed out at the bottom of the bed by a rotary airlock valve.In practice, a plurality of beds of moving granular media materials areutilized, generally from three to five depending upon the pollutantmake-up and volume in the gas stream, each bed functioning like theother. A last filter bed in the series to receive the gas stream flow ispreferably a static bed. The static bed, like the moving beds, is purgedwhen an appropriate pressure drop is sensed thereacross. The static bedis to serve as a final filter to remove any remaining particulates andis static to avoid any re-entrainment of collect particulate material asmay occur with a moving bed and so must be shut down prior to bedchanging. Alternatively, the invention, to provide for continuouslyoperating systems, may include a pair of static beds with separate flowpaths to each where the gas stream flow can be directed from one bed tothe other, allowing for a bed change of filter media materials withoutrequiring system shut down.

As set out above, the preferred system for practicing the method of theinvention is a closed system, with granular media materials making upeach moving bed to be replenished by new and recycled media materialthat has passed out of the system through a rotary airlock thatmaintains the system under a pressure that is less than atmospheric.Which preferred system can operate at any required temperature up toapproximately two thousand (2000) degrees F.

DESCRIPTION OF THE DRAWINGS

In the drawings that illustrate that which is presently regarded as abest mode for carrying out the invention:

FIG. 1 is block flow schematic view of an apparatus for practicing themethod of the invention for removing particulate matter and gaseouspollutants from a polluted gas stream showing a first charged drysorbent injection gun, power supply and controls and showing, in brokenlines, an optional second gun for injecting charged dry sorbentparticles into the polluted gas stream, that gas stream directed throughmultiple moving beds and a static bed of a filter media material thatremove agglomerized particles of pollution and sorbent particulates forprocessing and venting the cleaned air flow to atmosphere;

FIG. 2 is a profile perspective view of the apparatus of FIG. 1 showinga sorbent injection gun in solid lines and a second sorbent injectiongun in broken lines, and showing a side panel of a filter bed housingthat has been broken away to exposed sections of moving and staticfilter beds serially arranged therein;

FIG. 3 is a side elevation view of the apparatus of FIG. 2;

FIG. 4 is an enlarged side elevation view taken within the line 4--4 ofFIG. 2 showing the charged dry sorbent injection gun insulator exposedthrough a broken away section of the gun housing and showing a chargingwand fitted into a barrel thereof in broken lines;

FIG. 5 is an enlarged sectional view taken within the line 5--5 of FIG.4;

FIG. 5A is a view like FIG. 4 shown another embodiment of a charged drysorbent injection gun that is formed from a ceramic material; and

FIG. 6 is an enlarged sectional view of one of the moving beds takenalong the line 6--6 of FIG. 3.

DETAILED DESCRIPTION

FIG. 1 shows a block flow schematic view of a preferred apparatus forpracticing the method of the invention for removing particulate matterand gaseous pollutants from a polluted gas stream 10, hereinafterreferred to as apparatus 10. The apparatus 10 that the method of theinvention is preferably practiced on is a system of modules connectedtogether for performing steps of the process for the removal ofparticulate matter from a gas stream utilizing electrostatic techniques.The method of the present invention improves over prior systems thathave exhibited poor efficiencies in the removal of submicron particlesize particulates and greater, does so in a completely dry system thatdoes not generate acid mist, can be operated at high temperatures of upto two thousand (2000) degrees F., and provides for operating under lessthan atmospheric pressure to pull the gas stream therethrough.Additionally, the apparatus 10 provides for varying the charge on andthe flow rate of electrostatically charged sorbent particles that areinjected into the polluted gas stream for purifying any number andvariety of gas streams containing different pollutants. A combination ofmoving and static beds is provided for removal of essentially allpollutants from the different gas streams, to vent a clean gas toatmosphere and allows for an easy removal of the collected pollutantparticulates for use or for transport and for the recycling of bothsorbent materials and the media material that make up the moving andstatic beds, that may be composed of different media material.

Shown in FIGS. 1, 2 and 3, for practicing a first step in the method ofthe invention, the apparatus 10 includes a sorbent injection gun 11,hereinafter referred to as gun, that receives sorbent particulates froma hopper or bin 12 that have been pressurized at a blower and sorbentfeed block 12a and provides for electrostatically charging the particlesby passing them through a high voltage corona discharge that surrounds awand 13, shown best in FIGS. 4 and 5, that is contained within the gun11. The sorbent material is selected for reacting with the pollutants tobe removed from a polluted gas stream. For many applications fineparticulate lime is selected, as for example lime particles are suitablefor the removal of pollutants from a gas stream emitted by coke ovens,stinter plants or steel-making furnaces. Where, for coal-fired boilers,the selected sorbent material may be nacholite that will react withsulfur dioxide in the gas stream to form sodium sulfate that adheres tothe sorbent particles. The media material selected for the sorbent istherefor determined by the pollutants to be removed from that stream.Which sorbent is reduced to fine particles for passage from the sorbenthopper 12 to be electrostatically charged and injected into the gasstream, as set out below.

Shown in FIGS. 1 through 3, the next step in the process involvesinjecting the charged fine sorbent particles into a polluted gas streamthat flows into a tube 14 that receives the gas stream from a plantdischarge. Dependant upon the pollutant character and volume in thestream flow, a single gun 11 may provide a sufficient flow ofelectrostatically charged sorbent particles into that gas stream toprovide a proper electrostatic charging of all the particulates in thatflow, include submicron size particulates. Where a single gun 11 is notsufficient, even with a capability for an increase or decrease in thecharging field strength as the preferred gun 11 is capable of, a second,third of more sorbent injection gun or guns 11a, as shown in FIG. 2,each receiving a sorbent particle flow, can be arranged to feed sorbentparticles into the gas stream. Such second sorbent injection gun 11a, itshould be understood, is preferably identical to the gun 11 and so adescription of gun 11, its source of sorbent particles under pressure,and its functioning should be taken as a description of the secondsorbent injection gun 11a also.

The gun 11 and, as required, the second sorbent injection gun 11a,receive a flow of fine particulate sorbent materials from sorbent hopper12 that is pressurized, as shown in FIGS. 1 through 3, at a blower andsorbent feed 12a. In practice, the sorbent flow is pressurized tobetween 1 to 10 psi, as it flows into gun 11 through a sorbent inlet 15,as shown in FIGS. 4 and 5. The gun includes a smooth walled barrel 16that can be formed of a P.V.C. type plastic, silicon rubber, ceramic, orthe like, and wherein the wand 13 longitudinally centered. The chargedsorbent particles travel therefrom through a charged dry sorbentinjection module 14 and mix into the gas stream that is travelingthrough tube 30. The wand 13, as set out above, provides a high voltagecorona discharge that imparts a like strong electrostatic charge ontoeach of the sorbent particles. To provide for different volumes ofcharged sorbent particles as are needed to be entrained in the gasstream for a particular volume of pollutants in that gas stream, theflow rate of the sorbent particulates can be varied. Accordingly, forthe invention to accommodate, and properly charge to a strongelectrostatic charge, all of the sorbent particles, the voltage that ispassed to the wand 13 is preferably arranged to be variable. To providesuch a variable voltage to wand 13, as shown in FIGS. 1 through 3, apower control 17 connects to a high voltage power supply 18. The powercontrol 17 is, as shown in FIG. 3, is preferably a control panel wherean operator, not shown, can input a required voltage for a certainvolume of sorbent so as to provide a required strong electrostaticcharge to the individual sorbent particles, charging each negatively orpositively. In practice, the power control 17 is capable of varying thevoltage supplied to each gun 11 and sorbent injection gun 11a, or guns,to accommodate the flow of sorbent particles therethrough so as toprovide the required electrostatic change to which sorbent particles.

Shown in FIGS. 4 and 5, the preferred gun 11 includes a cylindricalinsulator housing 19 wherein is contained a high voltage insulator 20,that is shown mounted onto one end to a base 21 to extend longitudinallywithin the center of insulator housing 19. The opposite end of the highvoltage insulator is shown to include a connector 22 that is forelectrical connection to the high voltage power supply 18. The connector22 connects to a conductor that extends longitudinally through thecenter of the insulator 20, through a ceramic insulator 24, andelectrically connects, through a conductive coupling collar 25, to thewand 13 at end 13a. The wand is centered within the smooth walled barrel16 that is connected, on a rear end adjacent to the sorbent inlet 15, toa collar 31, and on a forward end through a plate 26 to a fitting 27that is bolted thereto, as shown at 28, containing the smooth walledbarrel 16 within a cylindrical housing 35. The fitting 27 connectsthrough a line 29 to the charged dry sorbent injection module 14 thatinjects the sorbent particles into the gas stream that passes throughtube 30. The smooth walled barrel 16 rear end connects through thecollar 31 to a cylinder 32 that itself contains the ceramic insulator.The cylinder 32, in turn, mounts, on its rear end, a coupling collar 33that is fitted through a forward plate 34 of the insulator housing 19and is bolted to a voltage insulator base 21 and to a flange end 35a ofthe cylindrical housing 35. The components of the preferred gun 11 arethereby contained within the respective cylindrical housing 35 andinsulator housing 19. The insulator housing 19, is shown capped acrossits rear end by an access plate 36 that includes a handle 37 extendingoutwardly therefrom. The respective components, as shown, are boltedtogether into the gun 11.

Shown best in FIG. 5, for a P.V.C. type plastic barrel 16, or the like,the sorbent inlet 15 is preferably bent through a right angle withrespect to the barrel 16. Which angle inlet angle, for a ceramic barrel16a and sorbent inlet 15b combination of a ceramic gun 11b, may beapproximately thirty (30) degrees from horizontal, as shown in FIG. 5A.Which ceramic gun 11b is otherwise like the gun 11 and accordingly thecomponents thereof are shown numbered the same as for gun 11. Thesorbent inlet 15 of FIGS. 4 and 5, in turn, mounts a coupling collar 15aacross its end opposite to its junction with barrel 16. A tube 38 thatmounts to an end plate 39 is shown telescoped into which coupling collar15a, the end plate 39 for closing over the end of a right angle port 40that is formed into the side of the cylindrical housing 35. The endplate 39 is shown to also include a mounting disk 41 secured thereto, onthe opposite end plate face to the tube 38, that is for receiving a likedisk 42 fitted and bolted thereto. The disk 42, in turn, mounts afitting 43 that connects to a sorbent feed line 44, for passing sorbentparticles from the sorbent hopper 12 that are pressurized in the blowerand sorbent feed 12a. In practice, the sorbent particles are transferredat a pressure of approximately 1 to 5 psi through sorbent feed line 44that has an approximate diameter of 2 to 3 inches, the flow travelinginto the barrel 16 that contains the wand 13 and has a diameter ofapproximately 2 to 3 inches. The preferred gun 11 for practicing theinvention provides a capability for varying the sorbent particle flow toa specific pollutant content of gas stream, and for varying theelectrostatic charge imparted onto the sorbent particles by operation ofthe control panel 17 to appropriately vary the voltage present at wand13 to provide a desired strong electrostatic charge to each sorbentparticle that is appropriate to the actual sorbent flow.

In practice, for a sorbent particle flow from 1 to several hundredpounds per hour, a voltage of 5,000 to several 100,000 volts is passedto wand 13, which voltage is dependent on the distance of the gun outletand the first bed and the relationship of size of particle in the gasstream that must be removed. The wand 13 thereby maintains a uniformhigh voltage corona discharge therearound along its entire length tonegatively or positively charge each sorbent particle passed throughbarrel 16.

The sorbent particles that pass by wand 13 absorb a strong electrostaticnegative or positive charge and are then injected through the chargeddry sorbent injection module 14 into the polluted gas stream. Therein,the sorbent particles that all bear the same negative or positive chargetend to repel one another and are thereby rapidly dispersed throughoutthat polluted gas stream. A utilization, as is preferred in a practiceof the method of the invention, of very fine-grained sorbent particlestends to significantly increase the sorbent's activity, considerablyreducing the residence time required for their complete dispersion intothe polluted gas stream. The charged particles themselves attract bothsubmicron and larger particulates in the gas stream, gathering them ontothe sorbent particles surface, thereby agglomerating them to form largerparticles. Additionally, the charged sorbent particles are also selectedfor chemically reacting with pollutants in the stream and provide alarge charged area for charging particulates that are not alreadyagglomerated. The gas stream and entrained sorbent is then directed intoa collection system 50 of the invention.

The collection system 50 wherein the steps of the invention for theremoval of pollution and sorbent particulates from the gas stream arepracticed is shown in FIGS. 1 through 3, is shown as preferablyincluding two distinct collection areas. A first collection area is atransition section 51 that receives the gas stream through a nozzle end52, that is the same diameter as the tube 30 wherethrough the gas streamand entrained pollution and sorbent particles travels. Walls 53 of thetransition cone slope outwardly to present a large square or rectangulararea that is opposite to the nozzle end. The transition section 51 isopen therethrough and preferably contains, centered therein, a diffusercone 51a that spreads the gas stream flow outwardly to cover the area ofa first filter bed 60, as set out below. The gas stream passing throughthe transition section 51 and around the diffuser cone 51a experiences aradical change in velocity from the nozzle end 52 to a large formedsquare or rectangular area of the first filter bed 60. With that changein velocity, heavier particle entrained in the gas flow tend to fall outof the flow in front of the first filter bed 60, as set out hereinbelow,that is positioned across to fill the area opposite to the transitionsection 51 large square or rectangular area. Which particles, asdiscussed below, are removed along with particles that have fallen outof the gas stream on contact with the face of the first moving bedfilter, along with the filter bed media materials, as set out hereinbelow.

Shown best in FIG. 2, the transition section 51 connects to one end of acollection chamber housing 54 that houses filter beds that are forremoving particulate matter from the gas stream in a practice of themethod of the invention, the gas stream then passed out an exhaustsection 55. The gas stream passing through exhaust section 55 is pulledthrough a vent tube 56 by a fan 57, with the now clean air vented outthrough a stack 58.

The collection chamber housing 54 is shown as having a rectangular boxarrangement with a number of spaced hoppers mounted along the housingtop 59 for passing materials into the filter beds contained in thehousing, as set out hereinbelow. The collection chamber housing 54contains a series of vertical filter beds 60, 61 and 62. Shown in FIG. 2and the enlarged sectional view of FIG. 6, the first filter bed 60 isopposite to nozzle end 52, between the ends of walls 53 to receive thegas stream from the nozzle end. The first filter bed 60 and second andthird filter beds 61 and 62, shown best in FIG. 2, are preferably movingbed filters, and a final or fourth filter bed 63 in the series ispreferably a static bed filter. While three moving filter beds are shownherein it should be understood that the invention can include one onlymoving bed to as many moving filter beds as are required to completelyclean the gas stream, and that a description of one of the moving filterbeds, specifically the first filter bed 60, and its accompanying feedbins, rotary valved discharge bin, media screen and return lines, shouldbe taken as a description of the other moving filter beds andaccompanying components also.

The first filter bed 60, as shown in FIGS. 2 and 6, includes a filter 65formed of a media material maintained between forward and backsideplates 67 and 68, respectively. The plates 67 and 68 are each punchedwith a number of holes 69 therethrough to allow for, essentially,unobstructed passage of the gas stream through the filter 65. The filter65 is preferably a gravel bed filter that is approximately twelve (12)inches thick and extends across and between top and bottom surface ofthe collection chamber housing 54. The media material of the filter 65is selected for removing the particular pollutants contained in apolluted gas stream and may be silica gravel, limestone gravel, anartificial material, and the like, within the scope of this disclosure,functioning as set out below and as illustrated in the includedexamples. The media material of which filter 65 may be the same for thefirst, second and third filter beds 60, 61 and 62, respectively, asshown in FIGS. 1 through 3, or may be of different materials asillustrated in the Examples 1 and 2 set out later herein.

Shown in FIGS. 1 and 2, the media making up the moving bed filter 60 ispassed into the top of the filter bed 65 from a rotary airlock 74 havingpassed through a surge hopper 70, shown in FIGS. 1 through 3, andtravels through the filter bed responsive to gravity and as controlledby operation of a rotary discharge valve 73, that is shown best in FIG.6 as a paddle wheel device that extends fully across the filter bed,from wall to wall, below the bed body, and is arranged above a catchmenthopper 72. In which travel the filter media material is moving crosscurrent to the direction of gas stream flow and is operated in a plugflow mode. Movement of the filter 65 is controlled by operation of therotary discharge valve 73, that, as set out above, is preferably apaddle wheel device though, of course, another valve arrangementsuitable for the described application could be so utilized. The rotarydischarge valve 73, as set out above, preferably extends across the bed,from one side to the other of the collection chamber housing 54.Additionally, another airlock 71 is preferably provided below the rotarydischarge valve 73, passing media materials and agglomerized particlesonto a media screen 75, the valves operating to provide a closed system.The closed system contained in the collection chamber housing 54 istherefore capable of and is preferably operated at less than atmosphericpressure to provide somewhat of a vacuum effect to pull the gas streamtherethrough. In practice, the system is preferably operated at from 1to 24 inches of water below atmospheric conditions. This operatingpressure provides for increased efficiency by pulling the gas streamthrough the filter 65, providing for an increase in the efficiency ofthe separation of pollutant gases entrained in the gas stream, that areprecipitated onto the surface of the filter media particles. A chemicalreaction for which reaction where hydrated lime or ammonia is used asthe sorbent material to remove SO₂ gas contained in the gas stream is asfollows:

    Ca(OH).sub.2 +SO.sub.2 →CaSO.sub.3 +H.sub.2 O

    2(NH.sub.3)+SO.sub.2 +H.sub.2 →(NH.sub.4).sub.2 SO.sub.3

The above reactions are facilitated by operation at less thanatmospheric pressure by the gas stream being drawn through the filterbeds. Further, the closed system facilitates operations at hightemperatures of up to two thousand degrees F. Which high temperatureoperations both significantly improve system efficiency and are aneffective bar to a generation of an acid mist as a product of a chemicalreaction as could damage the equipment, as for example, where sulfurdioxide is a pollutant being removed from a gas stream, as has been thecase with earlier systems. To maintain an operating pressure within thecollection chamber housing 54, the rotary discharge valve 73 controlsmedia material falling under the urgings or gravity between the frontand rear plates 66 and 67 as the rotary discharge valve 73 is operatedresponsive to a sensed pressure drop across the first filter bed 60 fromfeed hopper 70. When such pressure drop is sensed by sensors placed onforward and rear sides of the first filter bed, that indicates that thefilter 65 is plugging, the paddle wheel of the rotary discharge 73 isturned. The plugged filter media materials are thereby passed out of thefilter bed 60 and flow through the airlock 71 onto a media screen, asillustrated in FIG. 1, whose function will be set out hereinbelow. Mediamaterials from the feed hopper 70 to fill the area of the filter 65between the forward and backside plates 67 and 68.

Filter 65 movement above rotary discharge valve 73, as shown in FIG. 6,causes some media particles to be ejected through the openings 69 inplates forward and backside plates 67 and 68, respectively, therebykeeping those holes open to provide a free flow path to the gas stream.The ejected media particles fall, as shown, into the catchment skirt72a. Skirt 72a also receives the heavy particles that fall out of thegas stream on a reduction of the gas stream velocity in the transitionsection 53, and on contact of the gas stream with the forward plate 67.Which particles are mixed with the filter media materials that containagglomerized particles to pass through the rotary discharge valve 73.

Shown in FIG. 1, particulate and media materials pass from the catchmenthopper 72 through airlock 71 and are deposited onto a media screen 75.The media screen 75 passes the agglomerized particles and shakes offpollutant particles which have adhered to the media particles. Thecleaned media material particles are then moved through line 75a forrecycling back to the hopper 70 for refeeding back through the movingfilter beds 60, 61, and 62. Media material losses at the media screen 75are made up from a media hopper 76 that passes media particles throughline 77. The clean screened and added media material particles are thenpassed through line 78 upward to dump into a horizontal line 79 thatbranches into hopper feed lines 80 that dump the clean media materialsthrough airlocks 74 into individual hoppers 70, feeding each movingfilter bed 60, 61 and 62.

As set out above the description of the first filter bed 60 should betaken as a description of all the moving filter beds 60, 61 and 62. Inpractice, the first filter bed 60 will collect between seventy five (75)to ninety five (95) percent of the particulate material entering thecollection system 50, which collected material includes the sorbent andsorbent reacted particulates. The remaining moving filter beds 61 and 62to remove essentially the balance of the particulate material in the gasstream and to react with pollution gases therein. Accordingly, withdifferent sorbent flow rates, as provided for cleaning a certain gasflow, more or less than the three (3) moving filter beds can beincorporated into the collection system 50, within the scope of thisdisclosure. Also, for some applications it may be required or desirableto utilize a different size of media material particles from thatutilized in the first filter bed 60, and it may even be preferably toutilize different media material than that used in the first filter bed,as set out in Examples 1 and 2 below. Such utilization of different sizeof media material or of different type or types of media materials asthe filters for the individual filter beds will, of course, require autilization of a different media material replenishment arrangement thanthat shown in FIGS. 1 and 2, to include individual media hoppers 76 forreplenishing the bed materials as well as separate flow lines forfeeding the individual media material hoppers 70.

In FIG. 1 piles of material 81 are shown as having been screened out bymedia screen 75 and a static bed media screen 94 and are arranged beloweach screen, with lines 75a and 94a, respectively, shown for passingcleaned media material to the media hopper 76. The screened material 81containing the gas stream pollutants can then be processed forseparating the various constituents for recycling and reuse and/ordisposal, within the scope of this disclosure.

A static filter bed 85, shown in FIGS. 1 and 2, is provided within thecollection system 50, arranged across the interior of the collectionchamber housing 54, that receives the gas stream passed from the thirdfilter bed 62, and is to finally remove essentially all the sorbentparticles agglomerated particles and gaseous pollutants from the gasstream. Where, as set out below, the media material in the filter 86 ofstatic filter bed 85 can be changed, it is normally not changed duringan operation cycle as the materials it picks up during a cycle aregenerally insufficient to create plugging. The static bed is, however,periodically purged during system shutdown or when an appropriatepressure drop across the static filter bed 85 is sensed. The static bed85 is, or course, the same size as the moving filter beds 60, 61 and 62,and may be the same, greater, or lesser thickness, within the scope ofthis disclosure, with the filter of media material 86 contained betweenforward plate 88 and a backside plate that are preferably punch platesthat include a large number of holes 89 formed therethrough. The staticfilter bed 85 serves as a polishing filter that follows up the movingfilter beds. It is static because any movement of the bed, no matter howslow, will cause a re-entrainment of the collected particulatematerials. Accordingly, purging of the static filter bed is usuallyundertaken prior to system start-up or after shutdown. Additionally,where a system is to operate continuously two static beds dove-tailedtogether can be utilized, as illustrated by a broken line representationin the block flow schematic of FIG. 1. Shown therein in broken lines,the air stream is directed around the static filter bed 85 by fitting abaffle plate 90 into the collection chamber housing 50 to redirect airstream flow into a conduit 91 that directs the flow through analternative static filter bed 85a such that the air stream passesthrough exhaust conduit 91a into the exhaust section 55. With the airstream redirected around the static filter bed 85, the filter 86 can beemptied and refilled with clean media material and the flow therethroughrestored.

For static filter bed 85 purging, media inlet and outlet rotary airlockvalves 97 and 93, respectively, shown as arrows in FIG. 1, are providedfor passing static filter bed 85 media material therein and dischargingsame after system shutdown. Which valves are closed during systemoperation to prevent infiltration of outside air into the unit. Filtermedia material 86 is vented to a purge bin 92 that directs the flowthrough a valve 93, shown as an arrow, to a media screen 94. The mediascreen, like media screen 75, provides for the removal of agglomerizedparticles and provides for shaking off particulate matter from the mediamaterial. The clean media material is transferred through line 94a tothe media hopper 76, with the pile 81 of material deposited below themedia screen 94 for processing for recycling, reuse and/or disposal, asdescribed above. The clean media material is passed from the mediahopper 76 into a media material supply line 96 from media hopper 76.Additionally, where the media material in the purge bin 92 is clean, itcan be passed directly from the purge bin 92 through line 96 into mediasupply line. The recycled media material and unused media material arethereby transported by mechanical means through line 96 to an inletrotary airlock valve 97, shown as an arrow, for passage into supplypurge bin 98 that supplies clean media material to the static filter bed85, as described above. In operation, the static filter bed 85 is toremove agglomerized particles and gases collected from the gas streamand functions essentially as set out above for the moving filter beds60, 61 and 62, and so will not be further discussed.

Operation of the component systems of the apparatus 10 for performingthe steps of the method of the invention, as set out above, it should beunderstood, is provided by electrically operated devices, such asblowers and motors. Which devices, it should be understood, arerelatively low horsepower motors and/or require relatively lowhorsepower to operate, thereby proving a simple and robust system thatis inexpensive to use and maintain.

Examples of the steps involved in the operation of the apparatus 10 ofthe invention for removing essentially all pollutants in a gas streamare set out and discussed hereinbelow as Examples 1 and 2:

EXAMPLE 1

This is a hypothetical example of a practice of the method of theinvention for removing particulate matter and gaseous pollutantssimultaneously from a gas stream generated by a Copper Smelter utilizingthe preferred apparatus. Reference is hereby made to the apparatus ofFIG. 1 for practicing the steps of the method:

For this example, a polluted gas stream 30 having a flow rate of 35,000ACFM at a temperature of 350 degrees F., is cleaned by a practice of thepresent method. The gas stream has a particulate grain loading of 5.0gr./DSCF and a gaseous pollutant of SO₃ with a grain loading of 1.0gr./DSCF, as the primary pollutants is to be cleaned therefrom. Otherpollutants are associated with the gas stream, but are of minorimportance in the overall clean up of the gas stream. A modeling programis specifically designed and sized for a preferred apparatus forcalculating the material flow and volume of sorbents to be used forcleaning of a particular pollution content of a gas stream, the selectedsorbent material is Hydrated Lime Ca(OH)₂. The rate of feed for theelectrostatically charged hydrated lime for the example is 155 poundsper hour utilizing a single charged dry sorbent injection gun 11.

A first step in the method involves electrostatically charging a flow ofsorbent particles that are injected into the gas stream. For thisexample, one hundred fifty five pounds per hour of hydrated lime, finegrained -200 mesh, is feed from the sorbent storage hopper 12 to thecharged dry sorbent injection gun 11 where a electrostatic charge of80,000 volts is applied to the fine grained hydrated lime particles fromthe high voltage power supply 18. The voltage charge on the hydratedlime is determined from the results of a screen analysis on theparticulate matter pollutants that must be removed, the distance thecharging gun is located from the moving media first filter bed and theamount and type of sorbent used. The charge will be a variable charge,depending on site specific information that is part of the modelingprogram. In a next step, the hydrated lime after being electrostaticallycharged is feed into the charged dry sorbent injection module 14, whichfeeds the electrostatically charged hydrated lime into the polluted gasstream 30. The charged sorbent rapidly disperses into the gas stream,providing a large charged surface area for inducing the electrostaticcharge onto the particulate matter entrained within the incoming gasstream and to supply a large area for the chemical reaction between thesorbent and the gaseous pollutants to react in. The gas stream withentrained charged sorbent particles is then passed into a transitionsection 53, directed against a dispersal cone 51a to disperse the gasstream throughout the transition section. From the injection module 14to the transition section 53, a chemical reaction between the hydratedlime and the SO₃ takes place, creating CaSO₄, or gypsum, and the chargedhydrated lime sorbent agglomerates the particulate material, morespecifically the PM-10 particles. This area is more specifically calledthe residence area or zone, and may or may not contain a speciallyconstructed residence chamber.

The transition section 53 has a much greater area than the gas streamline, causing a rapid decrease in the gas flow velocity. This change invelocity causes some of the heavier particulate particles and sorbentreacted gaseous pollutants in the gas stream to precipitate out of thatflow, falling in front of a first of a plurality of vertical mediamaterial moving bed filters that receive the dispersed gas stream andwherein pollutants are first removed from the stream. The verticalmoving bed filters, in this case are charged with two types of mediamaterial, sized to -3/8 inch to +5 mesh. The first moving media bedfilter is charged with limestone, a product used by a copper smelter inthe smelting process, is used were to further enhance the reaction ofSO₃ and to insure maximum clean up of the gaseous pollutants from thegas stream, which clean up in the first moving filter bed isapproximately seventy five (75) percent, or greater of the pollutantspresent in the stream. Passage of the gas stream, in turn, through theremaining second and third moving bed filters and the static filterremove the remainder of the pollutants from the gas stream, the mediamaterial for which moving and static bed filters are slag, a by-productof copper smelting process, whose provides an optional method step inthat its use saves upon the screening costs of the material providing acost savings, and adds to the recovery of volatilized copper, gold andsilver, that is collected in this process, but is typically lost or notcollected in conventional pollution control systems or devices. Anypollutants that have no economic value will thereby be consumed in thesmelting process or entrained in the slag from the smelting process andlater disposed of when the slag is drawn off and transported to thesmelters slag disposal area, thus reducing handling problems associatedwith the disposal of collected fines and sorbent reacted material as inother processes.

The second and third moving media bed filters and the static media bedfilter material will be set up to recycle the slag, screening anycollected particulates and sorbent reacted gaseous pollutants from theslag media, providing for reusing the screened media material slag thatis sent back into the second and third moving media bed filters and thestatic media bed filter, respectively. The particulates and pollutantsscreened from the media material will be sent directly into the smeltingprocess to further recover any volatilized copper, gold and silver andto dispose of any particulates and collected pollutants of non economicvalue into the clients slag from the smelting process, as previouslymentioned.

EXAMPLE 2

This is a hypothetical example of a practice of the method of theinvention for removing particulate matter and gaseous pollutantssimultaneously from a gas stream generated by a Copper Smelter.Reference is hereby made to the apparatus of FIG. 1 for practicing thesteps of the method:

For this example, a polluted gas stream 30 having a flow rate of 50,000ACFM that is at a temperature of 800 degrees F. is cleaned by a practiceof the present method. The gas stream has a particulate grain loading of15.0 gr./DSCF and a gaseous pollutant of SO2 with a grain loading of 2.0gr./DSCF, (374 pounds/hour), as the primary pollutants to be cleanedtherefrom. Other pollutants are associated with the gas stream, but area minor importance in the overall clean up of the gas stream. A modelingprogram is specifically designed and sized for a preferred apparatus forcalculating the material flow and volume of sorbents to be used forcleaning of a particular pollution content of a gas stream, the selectedsorbent material is a Hydrated Lime Ca(OH)₂ and ammonia NH₃. The rate offeed of electrostatically charged hydrated lime and ammonia for theexample is 534 and 54 pounds per hour, respectfully, utilizing a twocharged dry sorbent injection guns 11 and 11a.

A first step in the method involves electrostatically charging a flow ofsorbent particles that are injected into the gas stream. For thisexample, three hundred fifty pounds per hour of hydrated lime, finedgrained, -200 mesh, is feed from the sorbent storage hopper 12 to thecharged dry sorbent injection gun 11 where a electrostatic charge of102,000 volts is applied to the fine grained hydrated lime particlesfrom the high voltage power supply 18. 184 pounds per hour of hydratedlime, fine grained, -200 mesh, is feed from the sorbent storage hopper12a together with 54 pounds per hour of ammonia gas to the charged drysorbent injection gun 11a where a electrostatic charge of 98,000 voltsis applied to the fine grained hydrated lime particles and ammonia gasfrom the high voltage power supply 18a. The voltage charge on thehydrated lime and the ammonia, is determined from the results of ascreen analysis on the particulate matter pollutants that must beremoved, the distance the charging gun is located from the first movingmedia filter bed and the amount and type of sorbents used. The voltagecharge is variable and is determined from site specific information thatis part of the modeling program. The hydrated lime and ammonia afterbeing electrostatically charged are fed into the charged dry sorbentinjection module 14 and 14a, which feeds the electrostatically chargedhydrated lime and ammonia into the polluted gas stream 30. The chargedsorbents rapidly disperse into the gas stream, providing a large chargedsurface area for inducing the electrostatic charge onto the particulatematter entrained within the incoming gas stream and to supply a largearea for the chemical reaction between the sorbents and the gaseouspollutants to react in. The gas stream with entrained charged sorbentparticles is then passed into a transition section 53, directed againsta dispersal cone 51a to disperse the gas stream throughout thetransition section. From the injection module 14 and 14a to thetransition section 53, a chemical reaction between the hydrated lime andammonia and the SO₂ takes place, creating CaSO₃, calcium sulfite+H₂ Oand (NH₄)₂ SO₃, ammonium sulfite and the charged hydrated lime sorbentalso agglomerates the particulate material, more specifically the PM-10particles. This area is more specifically called the residence area orzone, and may or may not contain a specially constructed residencechamber.

The transition section 53 has a much greater area than the gas streamline, causing a rapid decrease in the gas flow velocity. This change invelocity causes some of the heavier particulate particles and sorbentreacted gaseous pollutants in the gas stream to precipitate out of thatflow falling in front of a first of a plurality of vertical moving mediabed filters. The vertical moving media bed filters, in this case arecharged with two types of media material, sized to -3/8 inch to +6 mesh.The first moving media bed filter is charged with silica gravel, aproduct used in the smelting process. The remaining second and thirdmoving media bed filters and the static filter are charged with slag, abyproduct of copper smelting, which will be of a minimum of cost. Themedia material from the first moving media bed will be feed directlyinto the smelting process, since silica is a flux material used in thesmelting of copper concentrates, for this particular application. Thisdirect feeding from the first moving media bed filter into the smeltingprocess will save on the screening costs of the material, presenting acost savings, and will help in the recovery of volatilized copper, goldand other base metals, that are collected in this process, but aretypically lost or not collected in conventional pollution controlsystems or devices. Any pollutants that have no economic value will beconsumed in the smelting process or entrained in the slag from thesmelting process and disposed of when the slag is drawn off andtransported to the smelters slag disposal area, thus reducing handlingproblems associated with the disposal of collected fines and sorbentreacted material as in other processes.

The second and third moving media bed filters and the static media bedfilter material will be set up to recycle the slag, screening anycollected particulate and sorbent reacted gaseous pollutants from theslag media, providing for reusing the screened media material that issent back into the second and third moving media bed filters and thestatic media bed filter, respectively. The particulates and pollutantsscreened from the media material will be sent directly into the smeltingprocess to further recover any volatilized copper, gold, silver andother base metals and to dispose of any particulates and collectedpollutants of non economic value into the clients slag from the smeltingprocess, as previously mentioned.

While a preferred apparatus for practicing the steps of our invention ina method for removing particulate matter and gases from a polluted gasstream has been shown and described herein, it should be understood thatthe present disclosure is made by way of example only and thatvariations and changes thereto are possible without departing from thesubject matter coming within the scope of the following claims, and areasonable equivalency thereof, which claims we regard as our invention.

We claim:
 1. A method for removing particulate matter and gaseouspollutants from a polluted gas stream comprising the steps of, injectinga flow of electrostatically charged sorbent particles into a pollutedgas stream, which said sorbent is selected for the particular pollutantsin said gas stream with the volume of said sorbent particles selectedfor the quantity of pollutants in said gas stream and the chargingvoltage applied to said sorbent particles is variable to provide amaximum charge on each sorbent particle; passing the gas streamcontaining said charged sorbent particles into a transition section of acollection chamber housing, which said transition section widens fromits inlet to its exhaust end, providing for a reduction in gas streamvelocity passing therethrough causing heavy particulates to fall out ofsaid gas stream; distributing said gas stream over and passing said gasstream through a first moving bed filter containing a media materialthat is maintained vertically in said collection chamber housing acrosssaid transition section exhaust end wherein agglomerized pollution andsorbent particulates are removed during passage through said mediamaterial, which said media material in said first moving bed uponsensing of a set pressure drop across said filter is changed for cleanmedia material by operation of a rotary discharge valve that passes saidmedia material out of a bottom end of said first moving filter bed, withclean media material passing from a media material hopper above saidfirst moving filter bed through a top of said first moving filter bed,replenishing said media material as has passed through said rotarydischarge valve; passing said gas stream through at least one additionalmoving filter bed containing a media material that is arrangedvertically in said collection chamber housing, is opposite and parallelto said first moving filter bed and is essentially the same as andfunctions like said first moving filter bed, may include the same ordifferent media material as used in said first moving filter bed and isfor removing additional agglomerized pollution and sorbent particulatesfrom said gas stream; passing said gas stream through a static filterbed that contains the same or different filter media material as used inthe first and additional moving filter beds and is vertically maintainedin said collection chamber housing parallel to and immediately oppositeto a last of said additional moving filter beds, and said static filterbed media material is not changed during system operation and is tofinally remove essentially all remaining pollution and sorbentparticulates from said gas stream; and venting said gas stream as haspassed from said static filter bed to atmosphere.
 2. A method as recitedin claim 1, wherein the gas stream within the transition section isdispersed therein by passage around a diffusion cone that is maintainedin the center of and opposite to the inlet of said transition section,an apex of said diffusion cone to face said inlet wherethrough said gasstream enters said transition section.
 3. A method as recited in claim1, wherein the collection chamber housing has a rectangular shape, thevertical filter beds fitted from top to bottom and side to side therein,with each said filter bed for containing the media material have spacedapart parallel forward and backside plates that each have a plurality ofholes punched therethrough providing passage of the gas streamtherethrough, and said punched holes are each of a diameter to allowparticles of media material to leak therethrough for cleaning saidpunched holes so as to prevent their clogging.
 4. A method as recited inclaim 1, further including maintaining the pressure in the collectionchamber housing at a pressure that is less than atmospheric.
 5. A methodas recited in claim 1, wherein the media material in each moving bedfilter is changed by operation of the outlet rotary discharge valve thatprovides for turning a paddle wheel thereof that extends across thefilter bed, with said media material containing agglomerized pollutionand sorbent particles gravity fed therethrough and falls into acatchment hopper.
 6. A method as recited in claim 5, further includingpassing the collected media material containing agglomerized pollutionand sorbent particles onto a media screen that removes the agglomerizedpollution and sorbent particles from said media material, cleaning saidmedia material; and transporting said clean media material back to themedia material hopper for recycling through the moving bed filters.
 7. Amethod as recited in claim 6, further including adding new mediamaterial, as needed, to the cleaned media material for reuse in eachmoving filter bed.
 8. A method as recited in claim 1, further includingproviding a second static bed filter and ducting for temporarily routingthe gas stream around the static filter bed and into said second staticfilter bed to allow for the changing of said static filter bed mediamaterial without shutting off said gas stream upon a sensing of apressure drop across said static filter bed media that is sufficient towarrant changing said media material in said static filter bed; andrestoring said gas stream flow into said static filter bed after saidmedia material therein has been changed to clean media materials.
 9. Amethod as recited in claim 8, wherein the media material as has beendischarged from said static filter bed is passed onto a media screenmeans for screening out agglomerized particles pollution and sorbentparticles and collected reaction products for processing or disposal;and recycling said media material with newly added clean media material,as needed, for reuse in said static and second static filter beds.
 10. Amethod as recited in claim 1, wherein the media material is a silica,limestone gravel, slag, sinter ceramic or other appropriate natural ormanmade material.
 11. A method as recited in claim 1, wherein the mediamaterial used in the filter beds is selected for the removal of thepollutants in a particular gas stream.
 12. A method as recited in claim1, wherein the electrostatically charged sorbent particles injected intothe polluted gas stream are provided by a sorbent injection module thatincludes a source of sorbent particulates that includes a housingcontaining an electrostatic charging wand that is connected to avariable source of electrical power to produce a high voltage coronadischarge surrounding said wand that is appropriate for fully chargingall the sorbent particles injected into said polluted gas stream; andpassing a flow of sorbent particles, under pressure, through saidhousing that pass through said corona discharge surrounding said wandand are thereby fully electrostatically charged and into line connectingsaid housing into the pipe carrying the polluted gas stream.
 13. Amethod as recited in claim 12, wherein the housing is a cylinder thatcontains a tube fitted longitudinally therein that mounts the wandlongitudinally in the center thereof, said tube connecting into the linefor passing a selected volume of charged sorbent particles into thepolluted gas stream from the source of sorbent particulates that willfully react with all the pollution particulates present in the gasstream, said sorbent particles traveling into said cylinder to flowaround said wand.
 14. A method as recited in claim 13, wherein aplurality of sorbent injection modules are provided for connection intothe pipe carrying the polluted gas stream, each providing a volume offlow of electrostatically charged sorbent particles into said pollutedgas stream to react with all the pollution particulates present in saidparticular gas stream.